Karasinski J, Galas J, Semik D, Fiertak A, Bilinska B, Kilarski W M
Department of Cytology and Histology, Institute of Zoology, Jagiellonian University, Krakow, Poland.
Reprod Domest Anim. 2010 Dec;45(6):959-66. doi: 10.1111/j.1439-0531.2009.01468.x.
Connexin43 (Cx43) is a major protein of myometrial gap junctions. The number of Cx43 gap junctions increase dramatically with the onset of labour in association with development of synchronized uterine contractions. The formation of myometrial gap junctions follows an increase in the oestrogen to progesterone ratio indicating an important role of steroid hormones in regulating Cx43 expression at term. However, no relationship has been established between the expression of Cx43 in the non-pregnant myometrium and concentration of steroid hormones during the oestrous cycle. Here, we used immunofluorescence and Western blotting to analyse the expression of Cx43 gap junctions in the myometrium of pre-pubertal pigs (n = 7) and mature pigs at pre-ovulatory (n = 7), luteal (n = 5) and late luteal (n = 3) stages of the oestrous cycle. The number of Cx43 gap junctions calculated per 1 mm(2) of the myometrial section was low in pre-pubertal pigs and significantly higher (p < 0.022) in pre-ovulatory animals. In relation to pre-ovulatory animals the number of myometrial gap junctions was significantly lower (p < 0.019) at the luteal phase and correlated with significantly higher (p < 0.005) concentration of endogenous progesterone. Phosphorylated isoforms of Cx43 protein were expressed in the myometrium of pre-pubertal pigs and mature animals at pre-ovulatory and late luteal phases, while they were down regulated at the luteal stage. These results indicate that changes of Cx43 expression in the porcine myometrium during the oestrous cycle may be regulated by progesterone concentration and may contribute to the modulation of uterine motility.
连接蛋白43（Cx43）是子宫肌层缝隙连接的主要蛋白。随着分娩开始，Cx43缝隙连接数量急剧增加，同时伴随着同步子宫收缩的发展。子宫肌层缝隙连接的形成伴随着雌激素与孕酮比值的增加，表明甾体激素在足月时调节Cx43表达中起重要作用。然而，在发情周期中，非妊娠子宫肌层中Cx43的表达与甾体激素浓度之间尚未建立联系。在此，我们采用免疫荧光和蛋白质印迹法分析了青春期前猪（n = 7）以及处于发情周期排卵前（n = 7）、黄体期（n = 5）和黄体后期（n = 3）的成年猪子宫肌层中Cx43缝隙连接的表达。青春期前猪每1平方毫米子宫肌层切片中计算出的Cx43缝隙连接数量较低，而排卵前动物中的数量显著更高（p < 0.022）。与排卵前动物相比，黄体期子宫肌层缝隙连接数量显著更低（p < 0.019），且与内源性孕酮浓度显著更高（p < 0.005）相关。Cx43蛋白的磷酸化异构体在青春期前猪以及排卵前和黄体后期成年动物的子宫肌层中表达，而在黄体期则下调。这些结果表明，发情周期中猪子宫肌层Cx43表达的变化可能受孕酮浓度调节，并可能有助于调节子宫运动。
